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Jun 19, 2010

Chek Jawa seagrasses after the oil spill (19 Jun 10)

Today, the Team heads off to monitor Chek Jawa after the oil spill that hit this shore about three weeks ago. How are our seagrasses doing? While earlier reports by shore lovers and in the media suggest no major immediate impacts, effects of an oil spill can develop over the long term.As the more experienced Team members do a quick survey of the rest of Chek Jawa, this means some of our newer Team members have to lead the monitoring.

The day begins with a quick revision on how to use the GPS, with Wei Ling patiently explaining how it is done.Then as the bulk of the Team head for the monitoring sites, Andy, Chay Hoon and I head off to do a broader survey.

I check out the southern side of Chek Jawa near House No. 1. There used to be large patches of the rare Beccari's seagrass (Halophila beccarii) here. Did they survive the oil spill? I was glad to see that there were still large patches of them. Here's one patch circled in yellow.This tiny seagrass is often mistaken for scum! It is very rare globally and we are very lucky to have lots of them on Chek Jawa. And I'm glad they seem to have survived the oil spill, so far.Those I saw seemed normal. They were green, and while some had dark bars, I have seen this kind of pattern in the past.As I check out the meadows of Spoon seagrasses (Halophila ovalis) near House No. 1, alas, I notice lots of patches of pale seagrasses.The leaves of some of the Spoon seagrasses have turned transparent!This must be the 'bleaching' of seagrasses that Len of Seagrass-Watch told me to look out for as one of the signs of oil spill effects on seagrasses.'Bleaching' happens when the seagrasses lose their chlorophyll, the green pigment that helps them undergo photosynthesis. Of course, this not good for seagrasses.There are patches of 'bleached' Spoon seagrasses on the meadows in front of House No. 1 on both sides of the jetty there. Even some of the Lettuce seaweed (Ulva sp.) is also bleached. Siti believes the 'bleaching' is in patches because these are probably where crude might have settled on the meadows.The tide was rather high today, so I couldn't tell if the bleaching happened all the way out to the sand bar near the beacon.

Closer to the boardwalk, there were some Needle seagrass (Halodule sp.). They looked fine.On the way back to the Information Kiosk, I have a look at the large meadows of Smooth ribbon seagrass (Cymodocea rotundata). The meadow is still quite large.The leaf blades looked alright, with no 'bleaching'. Although many were pale at the base of the leaves. And there were many leaf blades washed ashore, broken off at the base.I didn't see much Fern seagrass (Halophila spinulosa) where I walked, but the others saw some on the northern side. I also didn't get a chance to check up on the Sickle seagrass patch (Thalassia hemprichii) as it's on the northern shore. Nor the Tape seagrass (Enhalus acoroides) which are found near the beacon as the tide was too high today.

I didn't get a chance to take any photos of the Team at work. By the time I was done with the quick survey, the Team was also done and getting ready to go back.I also checked up on signs of oil spill effects on the mangroves, and other marine life on Chek Jawa. Meanwhile, Andy and Chay Hoon also did a survey of oil spill effects on the northern parts of Chek Jawa. See links below for more of our reports.

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